PCE R. Chen
Internet-Draft ZTE Corporation
Intended status: Standards Track S. Sidor
Expires: 28 January 2023 Cisco Systems, Inc.
C. Zhu
ZTE Corporation
A. Tokar
M. Koldychev
Cisco Systems, Inc.
27 July 2022
PCEP Extensions for sid verification for SR-MPLS
draft-chen-pce-sr-mpls-sid-verification-05
Abstract
This document defines a new flag for indicating the headend is
explicitly requested to verify SID(s) by the PCE.
Status of This Memo
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This Internet-Draft will expire on 28 January 2023.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. SID verification flag(V-Flag) . . . . . . . . . . . . . . . . 3
3.1. V-Flag in SR-ERO Subobject . . . . . . . . . . . . . . . 3
3.2. V-Flag in SR-RRO Subobject . . . . . . . . . . . . . . . 3
3.3. SID verification Processing . . . . . . . . . . . . . . . 3
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5.1. SR-ERO Subobject . . . . . . . . . . . . . . . . . . . . 3
5.2. LSP-ERROR-CODE TLV . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
[I-D.ietf-spring-segment-routing-policy] describes the "SID
verification" bit usage. SID verification is performed when the
headend is explicitly requested to verify SID(s) by the controller
via the signaling protocol used. Implementations MAY provide a local
configuration option to enable verification on a global or per policy
or per candidate path basis.
[RFC8664] specifies extensions to the Path Computation Element
Communication Protocol (PCEP) that allow a stateful PCE to compute
and initiate Traffic-Engineering (TE) paths, as well as a Path
Computation Client (PCC) to request a path subject to certain
constraints and optimization criteria in SR networks.
This document defines a new flag for indicating the headend is
explicitly requested to verify SID(s) by the PCE.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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3. SID verification flag(V-Flag)
3.1. V-Flag in SR-ERO Subobject
Section 4.3.1 in Path Computation Element Communication Protocol
(PCEP) Extensions for Segment Routing [RFC8664] describes a new ERO
subobject referred to as the "SR-ERO subobject" to carry a SID and/or
NAI information. A new flag is proposed in this doucument in the SR-
ERO Subobject [RFC8664] for indicating the pcc is explicitly
requested to verify SID(s) by the PCE.
V(1bit,TBD1): When the V-Flag is set then PCC
MUST consider the "SID verification".
3.2. V-Flag in SR-RRO Subobject
The format of the SR-RRO subobject is the same as that of the SR-ERO
subobject, but without the L-Flag, per [RFC8664].
The V flag has no meaning in the SR-RRO and is ignored on receipt at
the PCE.
3.3. SID verification Processing
On receiving an SRv6-ERO with the V-flag is set, a PCC MUST verify
SID(s) as described in Section 5.1 in
[I-D.ietf-spring-segment-routing-policy].
If a PCC "Verification fails" for a SID, it MUST report this error by
including the LSP-ERROR-CODE TLV with LSP error-value "SID
Verification fails" in the LSP object in the PCRpt message to the
PCE.
4. Acknowledgements
We would like to thank Dhruv Dhody and John Scudder for their useful
comments and suggestions.
5. IANA Considerations
5.1. SR-ERO Subobject
This document defines a new bit value in the sub-registry "SR-ERO
Flag Field" in the "Path Computation Element Protocol (PCEP) Numbers"
registry.
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Bit Name Reference
--- ----------------------- --------------
TBD1 SID verification(V) This document
Figure 1
5.2. LSP-ERROR-CODE TLV
This document defines a new value in the sub-registry "LSP-ERROR-CODE
TLV Error Code Field" in the "Path Computation Element Protocol
(PCEP) Numbers" registry.
Value Meaning Reference
--- ----------------------- -----------
TBD2 SID Verification fails This document
Figure 2
6. Security Considerations
TBD.
7. Normative References
[I-D.ietf-spring-segment-routing-policy]
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
P. Mattes, "Segment Routing Policy Architecture", Work in
Progress, Internet-Draft, draft-ietf-spring-segment-
routing-policy-22, 22 March 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
segment-routing-policy-22>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>.
Authors' Addresses
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Ran Chen
ZTE Corporation
Nanjing
China
Email: chen.ran@zte.com.cn
Samuel Sidor
Cisco Systems, Inc.
Email: ssidor@cisco.com
Chun Zhu
ZTE Corporation
Nanjing
China
Email: zhu.chun1@zte.com.cn
Alex Tokar
Cisco Systems, Inc.
Email: atokar@cisco.com
Mike Koldychev
Cisco Systems, Inc.
Email: mkoldych@cisco.com
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